1. Field of the Invention
The present invention relates generally to structural components associated with wheelchairs and the like. The present invention relates more specifically to movable arm rest assemblies associated with wheelchairs and the like, especially those capable of being locked into position.
2. Description of the Related Art
The structural components of wheelchairs and the like vary significantly depending upon the manufacturer and depending upon the specific requirements the wheelchair is designed to fulfill. Among the most basic structural components associated with nearly every wheelchair, however, are seat platforms, back rests, arm rests, leg rests, and of course, wheel components. Various structural assemblies for each of the basic components are well known in the art. Most of these structures are defined by and derive from the functions associated with the components.
Arm rests in particular are structured to provide suitable support to an individual seated within the wheelchair and in particular to provide lateral or side-to-side enclosures to facilitate the safety and comfort of the individual within the chair. While side arm rests serve the primary function of safely and comfortably positioning the wheelchair occupant on the wheelchair seat, they also must be structured so as to permit easy entry to or exit from the wheelchair. In some cases, entry to or exit from the wheelchair can be accomplished from the front without regard to the position of the arm rests. In many other cases, however, structures associated with the wheelchair prevent easy access to and from the seat of the chair from the front and require some type of access from the side over or around the arm rest assemblies.
Many wheelchair designs therefore have structured arm rests that are capable of being rotated out of the way in order to allow access to the seat area of the chair. In most cases such movement of the arm rest entails rotation about an attachment point on the back of the chair in a manner that lifts the arm rest up and back to provide access. Various rotational stops are well known that serve to limit this motion of the arm rest to a defined range.
A problem, however, with most such rotating arm rests is that they fail to provide adequate rigidity or support when movement is not desired. In many instances the arm rest of the wheelchair is used to support, position, and assist in the movement of the wheelchair occupant. If the arm rest too easily rotates up and back, it fails in its function as a support component.
It is desirable, therefore, that the arm rest, if rotatable to provide access, should be capable of being locked in a downward or lowered position in order to provide sufficient rigid support to the user. There have been various attempts at providing locking mechanisms at the rotation or pivot attachment point for the arm rest on the wheelchair. Such attempts have either failed because of their complexity or because of their inability to withstand repeated use or significant rotational forces. Other attempts have failed because the various mechanisms for locking or unlocking the arm rest are complicated, cumbersome, and difficult to manipulate.
It would be desirable to have an arm rest structure that provided sufficient rigidity and strength when in a lowered position such that forces tending to lift the arm up and back would not rotate the arm rest unless a locking mechanism was released. It would be desirable if such a locking mechanism were easy to manipulate and did not require complicated release or lock setting structures.